Car-brake adjuster



(No Mdel.) 'A l J. MACBBTH.

GAR BRAKE ADJUSTER. l

Patented Mm. 10,1896.

if?, lllllllllllllllllll j Alll Nrrnn STATES.

PATENT OFFICE.

JAMES MACBETII, OF BUFFALO, NEV YORK.

-eAR-BRA'KE ADJUSTER.

lsrr:crrcn'rron forming part of Letters Patent Np.- A556,011, daten Mar/ch io, 189e. l.Application led .lanuary 11,1896. Serial llo. 575,062. (No model.)

To @ZZ whom t may concern: 4 Be it known that I, J AMES MAcBE'rH, a citizen of the United States, residingat Bualo, in the eountyof Erie and State of New York, have invented a new andnseful Improvement in Car-Brake Adjusters, of which the following is a specification.

This invention relates to car-brake adjusters whereby the slack in the brake-gearing is automatically takenv up so as to insure proper working of theV brakes.

The obJ eet of my invention is to produce an automatic brake-adjuster which is particu-` larly applicable to the brake gearing of freight-earsqin which the piston-rod is loosely connected wlth the piston inthe brake-cylin-` der. 1

In the accompanying drawings, Figure lis a vertical longitudinal section of a, freight-car with my improved brake-adjusting mechanism;` Fig. 2 is a top plan View of the same, partly in section.V

Fig. 3 is a fragmentary side elevation of 4the brake-cylinder and connecting parts. Fig. 4

is a fragmentary horizontal section in line 4' 4, Fig. l. l

Like letters of reference refer to like parts 1 in the several figures.

A represents the brake-cyliiuler secured to the under side ofthe carin a horizontal positionV and provided with an air-pipe opening into its rear end.

B represents the brake-piston arranged in the brake-cylinder and provided wi th a hollow or tubular piston rod I), which passes through the front head of the cylinder. This piston is moved forward for applying the 'brakes bythe pressure of the air against the rear side of the piston. and is moved baek- Wardly for releasing the brakes by a spring h' surrounding'the hollow piston-rod and bearing with its ends against the front side of the piston and the front head of the cylinder.

C represents a tubular thrust bar or sleeve arranged within the hollow piston-rod and having its outer end projecting beyond the outer end of the piston-rod. The thrust-bar and piston-rod are capable of a limited length` avise movement upon each other to permit the piston during the initial portion of its forward movement to move idle withoutaifecting the brakes until it passes the leakagegroove in the cylinder in the usual manner and 1,30 Plmt 0f taking up the slack during by means of Astops c arranged on the outer.

end of the piston-rod on diametrically-oppo site sides thereof and projecting into longitudinal slots c', formed in the thrust-bar and adapted to engage with front and rear stops c2 c3, formed by the ends of the slots. When the brakes are released, the rear ends or stops c3 of the lslots in the thrust-bar are in engagement with the stops of the piston-rod and the inner end-of the thrust-bar is separated from This limited movement of the v the front side of the piston about the same' .distance as the length of the slots c', as rep-V resented in Fig. l. 4

c4 is a spring whereby the piston-rodi and thrust-bar are yieldinglygheld in this relative position and which cushions the piston as it moves againstv the end of the thrust bar. Thisspring bears with oneend against the front s'iderof the piston and with its other en d against a shoulder e5 formed on the inner por tion of the thrust-bar.

I) represents a clutch-bar'arranged with its rear end in the thrust-bar and supported at its front end by a bracketdl secured to the under side of the car.

This clutch-bar is provided on the upper side of its rear portion with ratchetteeth d', having inclined frontl sides and abrupt rear Sides.

E represents a couplingor take-up pawl pivoted on the outer end of the thrust-bar and engaging with the teeth of the clutch-bar.

F represents the main brake-lever having one of its arms connected with the draft-rodsv` j i ff which are connectedovith the brake-shoes by intermediate mechanism,and its other arm connected with the draft-rod f2 which is connected' with they hand wheel, whereby the brakes may be applied by hand in the'nsual manner.

mitted from the latter to'r the leve`r in line with the thrust of the piston. The preferred The brake-lever is connected with. the elutelrbar, so that the pressure is trans roo means for accomplishing this re'suit consists "in providing the lcentral portion of the clutchbar with a loop g, through which th\ brakepressed air into the rear end of the cylinder for applying the brakes the piston is moved forward and the springsb and cf are compressed. During the first portion of the forward movement of the piston the latter moves alone until it passes the usual leakage-groove in the cylinder and until its front side engages with the inner end of the thrust-bar, after which the piston and thrust-bar move together to the end of the forward stroke. The' forward movement of the thrust-bar is transmitted by the pawl to the clutch-bar and from the latter to the brake-shoes by the intermediate brakc-gcarin g. During the first or idle portion of the forward movement of the piston the stops on its tubular piston-rod move-from the rear ends to the front ends of the slots in the thrust-bar. Upon relieving the air-pressure for releasing the brakes the `piston is moved backwardlyito the end of its of the brakegearing upon releasing the brakes takes place slowly and is practically of the same extent every time the brakes are released. The extent of the forward movement, so that the piston and" its rod always begin the forward stroke at the same place. When the brake-shoes are in the' proper' relative position with reference to the car-wheels the extent of the forward and backward movelment of the clutch-bar and thrust-bar is practically the same, so that these two members also begin the forward stroke at the same place.

The extentl of the forward movement of the clutch-bar varies according to the amount of wear on the shoes; but this bar is not always moved backwardly to the same place where it befran its forward movement, because the backward movement is produced solely by the relaxation of the brake-gearing, which is practically the same every time the brakes are released. The extent of the forward movement of the thrust-bar also varies according to the condition of the brake-shoes in the same measure as the clutch-bar, but it is always 4. moved back to the same place at which it bey gins its forward stroke.

of the forward and backward movement of the clutch-bar and thrust-bar is the same their relation is not disturbed, and under these circumstances the backward movement of the thrust-baris produced solely by the relaxation of the brake-gearing, which movement it receives by the pawl from the clutch-bar.

'During'the last portion of the backward movement of the piston the latter moves in-l dependently 'of the thrust-bar and the stops' on its tubular piston-rod move from the front ends to the rear ends of the slots in the thrustbar. -The latter is restrained by the spring c4 from being.moved backward with the piston by frictional contact therewith during the normal condition of the brakes. In the normal condition of the brakes the extentof the forward movement and the subsequent backward movement of the thrust-bar andclutchbar is such` that the stops ofgthe piston-rod during the last portion of its backward movement with the piston will not en gage with the rear ends of the slots in the thrust-bar, whereby the relative position of the clutch-bar and thrust-bar is left undisturbed.

If the brake-shoes have become worn considerabl y the forward movement of the clutch and thrust bars isinereased i n the same mea-sure, but the clutch-bar docs not move backwardly to the same extent, because its backward movement is practically uniform at all times and is only so much as is produced by -the relaxing of the brake-gearing,'thereby causing the place at which the clutch-bar beginsits next forward movement to be advanced to the extent of the wear onthe brakeshocs. Although the/thrust-bar has been also moved forwardly an abnormal distance by the ,wear ony the brake-shoes it is nevertli'eless moved backwardly to the beginning `of its forwardstroke by the stopsfof the piston-rod engaging with the rear ends of the slots in the thrust-.bar and carrying the latter IOO,

along with it to the end of its backward stroke.

This causes the thrust-bar to be moved rearwardly on the clutch-bar and the pawl to be shifted from one tooth on the clutch-bar rearwardly to the next tooth, thereby lengthening thedistance between the piston andthe brakelever and taking up the wear on the brakeshoes' accordingly. After the slack in the brake-gearing has been taken up thestops of the piston-rod during the idle portion of its movement in applying and releasing the brakes continue to move back and forth vin the slots without engaging with thev ends thereof and' shifting the adjusting-sleeve until the wear on the brake-shoes is again sufficient to require the same to be taken up.

In the operation of the adjustingmechanism the brake-gearing is fully relaxed before the piston and its rod reach the end of their backward stroke, thereby `preventing the stops of the piston -rod from engagingwith the rear end of the slots in the thrust-bar and shifting the latter when the brake-shoes are in proper condition.

IIO

nected with the brake-gearing and having aV lengthwise movement with reference to the thrust-bar and a clutch device connecting the thrust and clutch bars, substantially as set forth.

The combination with the brakecylinder and piston, of a thrust-bar having'a limited longitudinal movement with reference to the piston, a spring whereby the piston and the thrust-bar are yieldingly held apart, a clutch-bar connected withthe brake-gearing and having a lengthwise'movement with reference to the thrust-bar and a clutch device connecting the clutch-bar and thrust-bars substantially as set forth.

4. The combination with the brake-cylinder and the brake-piston provided with a hollow piston-rod, of a thrust-bar having a limited lengthwise movement in the v4piston-rod, a spring interposed between the thrust-bar and the piston, a clutch-bar connectedy with the brake-gearing and a clutch device connecting the thrust and clutch bars7 substantially as set forth.

5. The combination with the hrakecylinder, the brake-piston and the hollow piston? rod provided with a stop or projection, of a thrust-b r arranged in the hollow piston-rod and provided with a longitudinal slot which receives the stop or projection of the piston rod, a clutch-bar connected with the brake gearing and a clutch device connecting the clutch and thrust bars, substantially as set forth. l c.

6. The combination with the bralecylin der, the brake-piston and the hollow piston rod, of a hollow thrustbar having a limited lengthwise movement with reference to the piston-rod, a clutch-bar connected with the brake-gearing and arranged in said 'thrustn bar and a pawl pivoted on thefthrust-har and engaging with, teeth on the clutchbar, sub-- stantially as set forth.

7. The combination with the brake-cylinder,` the brake-piston, the hollow pistoimfod provided'with a stop or projection and the spring whereby the piston is moved back- -wardly, of a hollow thrust-bar arranged in the hollow pistonand provided with longitudinal. slot which receives the stop or projection on the piston-rod, a spring interposed between the piston and the thrustbarj a clutch-bar 4arranged in said thrust-bar and connected with the brake-gearing and a pawl pivoted on the thrust-bar and engaging with teeth on the clutch-bar.Y substantially as set forth.

ber, 1895.4 Y

JAS., MAGBE il.

Witnesses:

Trino. L. Por?, KATHRYN'ELMORE,

fitness my hand this 30th day of Decem- 

